Chaos has a Name by Morgan Kelley

WARNING: This is the 66th book in a series classified EROTICA. If you’re looking for a cozy novel, these characters are NOT the ones for you. This book contains M/F M/M and reverse harems. You’ve been warned.

When Elizabeth finds out her father-in-law is dying, and he’s refusing to fight for his life, or them, that means the whole family needs to shift coasts and head to him. Moving everyone is a logistical nightmare, but she’ll do it for the man she calls ‘Dad’.
Heading back to FBI West is like torture. She and Ethan ran from there years ago, swearing never to return. The memories there were just too difficult to deal with, so they put it all behind them.
And now, they are back.
Oh, and it was just like she remembered.

PROBLEMATIC.
Right out the gate, she’s given the mother of all hellish cases, and, of course, it’s going to deal with the reservation. So now, not only is she on edge, but Callen and Ethan are too. As she chases the crazy, trying to figure out how someone can go missing every year on the Solstice, she also needs to fight for Wyler.
And that’s not going so well.
As she begins digging into the case, what she finds is horrifying, and goes against everything she’s fought for in her life. Where is the justice? Where is the balancing of scales?
And in the end, as it all hits the fan, she knows one thing.
Chaos has a name—and it’s most definitely BLACKHAWK.
If she survives this case, she’s made one promise.

Elizabeth is NEVER coming back to FBI West again, and nothing in the world can make her.